# File.open("test.rb") if File::exists?( "test.rb" )
puts File.file?( "text.txt" )
puts File.readable?( "test.txt" )  
puts File.writable?( "test.txt" )   
puts File.executable?( "test.txt" ) 

puts Dir.pwd
# 一个目录
puts File::directory?( "/1_school" ) 
 
# 一个文件
puts File::directory?( "input.txt" ) 